Taking Your Moissanite to a Jeweler: What to Expect, What Tests They'll Run & How to Respond

You've just received your moissanite ring. It's extraordinary — exactly what you hoped for. And then someone suggests taking it to a jeweler to "get it checked." Maybe it's a well-meaning family member. Maybe it's your own curiosity. Maybe you want to get it appraised for insurance purposes. Whatever the reason, you find yourself wondering: what exactly is going to happen when the jeweler puts that tester on my stone?

This guide answers that question completely — what tests jewelers use, what results you'll get with moissanite, and how to handle the conversation with confidence and accurate information.

The Two Types of Gemstone Testers

Most jewelers use one or both of two types of testers when evaluating a stone. Understanding the difference between them is the key to understanding what will happen when your moissanite is tested.

Type 1: The Thermal Conductivity Tester

The thermal conductivity tester — sometimes called a "diamond tester" — is the most common tool used by jewelers to distinguish diamond from imitations. It works by measuring how quickly a stone conducts heat away from a heated probe. Diamond conducts heat extremely efficiently, which is why it feels cool to the touch and why the thermal tester registers it as a conductor. Most diamond imitations — glass, cubic zirconia, synthetic sapphire — are thermal insulators and register differently on the tester.

Here is the critical fact that every moissanite owner needs to know: moissanite also conducts heat efficiently, and it will register as a conductor on a standard thermal conductivity tester — the same result as diamond.

This is not a flaw or a deception. It is a physical property of silicon carbide (SiC), the compound from which moissanite is made. Moissanite's thermal conductivity is similar to diamond's, which is why it passes the standard diamond tester. A jeweler using only a thermal conductivity tester cannot distinguish moissanite from diamond with that tool alone.

Type 2: The Electrical Conductivity Tester (Moissanite Tester)

A more sophisticated tester — sometimes called a "moissanite tester" or a combined thermal/electrical tester — measures both thermal and electrical conductivity. This is where moissanite and diamond diverge: diamond is an electrical insulator (it does not conduct electricity), while moissanite is a semiconductor (it conducts electricity weakly). A combined tester can detect this difference and will identify moissanite as moissanite rather than diamond.

Not all jewelers have this more sophisticated tester. Many still use only the basic thermal conductivity tester, which cannot distinguish moissanite from diamond.

What Will Actually Happen at the Jeweler

Scenario 1: The Jeweler Uses Only a Thermal Tester

If the jeweler uses only a standard thermal conductivity tester, your moissanite will register as a conductor — the same result as diamond. The jeweler may tell you the stone "tests as diamond" or "passes the diamond test." This is technically accurate — moissanite does pass the thermal conductivity test — but it does not mean the stone is diamond. It means the stone conducts heat efficiently, which both diamond and moissanite do.

If you know your stone is moissanite and the jeweler tells you it "tests as diamond," you can simply explain that moissanite passes the thermal conductivity test because of its similar thermal properties to diamond. This is a well-known fact in the gemological community, and any experienced jeweler will be familiar with it.

Scenario 2: The Jeweler Uses a Combined Tester

If the jeweler uses a combined thermal/electrical tester, your moissanite will be identified as moissanite. The tester will show a different reading than diamond, and the jeweler will tell you the stone is moissanite rather than diamond. This is the correct result — your stone is moissanite, and the tester is accurately identifying it.

Some buyers feel anxious about this scenario, as though being identified as moissanite is somehow a negative outcome. It isn't. Moissanite is a genuine, valuable gemstone with its own identity and its own extraordinary properties. Being identified as moissanite is not a failure — it is an accurate identification of what you have.

Scenario 3: The Jeweler Uses Visual Inspection Under Magnification

An experienced gemologist can often identify moissanite through visual inspection under magnification, without any electronic tester. Moissanite has a specific internal structure — needle-like inclusions that run parallel to the crystal's growth direction — that is different from diamond's internal structure. Under a 10x loupe, a trained eye can often distinguish the two stones.

Moissanite is also doubly refractive — it splits light into two rays as it passes through the crystal — while diamond is singly refractive. Under magnification, this double refraction appears as a slight doubling of the facet edges when viewed through the stone. This is a reliable visual indicator of moissanite that an experienced gemologist will recognize.

How to Handle the Conversation Confidently

The most important thing to know before taking your moissanite to a jeweler is this: you don't need to be defensive about what you have. Moissanite is a genuine, GRA-certified gemstone with extraordinary optical and physical properties. You chose it deliberately, and you have documentation to prove exactly what it is and what grade it carries.

Here is how to handle the most common scenarios:

If the Jeweler Seems Unfamiliar with Moissanite

Some jewelers — particularly those who work primarily with diamonds — may be less familiar with moissanite than you'd expect. If this happens, you can simply explain: "It's moissanite — silicon carbide, lab-grown, GRA certified at D-color VVS1. It passes the thermal conductivity test because its thermal properties are similar to diamond's." This is accurate, concise, and demonstrates that you know exactly what you have.

If the Jeweler Questions the Stone's Value

Some jewelers may suggest that moissanite is "just a simulant" or "not a real gemstone." This is inaccurate. Moissanite is a genuine gemstone — silicon carbide — with its own distinct identity, its own GRA certification, and its own extraordinary properties. It is not a fake diamond. It is a different stone that happens to look similar to diamond. You can politely correct this mischaracterization with the facts.

If You're There for an Appraisal

For insurance appraisal purposes, bring your GRA certificate. The certificate provides the independent, third-party documentation of the stone's grade that appraisers need to establish value. A GRA-certified D-color, VVS1, Excellent cut moissanite has a verifiable, documentable value that any competent appraiser can work with. For more on insurance and appraisals, see our article on insurance, appraisals, and protecting your investment.

The GRA Certificate: Your Best Tool

The single most useful thing you can bring to any jeweler visit is your GRA certificate. It is an independent, verifiable document that tells the jeweler exactly what your stone is, what grade it carries, and how to verify that information through GRA's online system. It removes any ambiguity from the conversation and establishes the stone's identity and quality on the basis of independent laboratory testing rather than the jeweler's personal assessment.

Every Moissanite Shine stone comes with a GRA certificate. If you've misplaced yours, contact our team and we'll help you retrieve the certificate information. For a complete explanation of what the GRA certificate includes and how to verify it, see our article on GRA certification explained.

The Bottom Line

Taking your moissanite to a jeweler is not something to be anxious about. You have a genuine, certified gemstone with extraordinary properties, and you have the documentation to prove it. The tester results — whether the stone passes as a conductor on a thermal tester or is identified as moissanite on a combined tester — are both accurate outcomes that reflect the real properties of what you have.

Know your stone. Know your certificate. And walk into that jeweler's shop with the confidence of someone who made a deliberate, informed choice — because that's exactly what you did.

For more on moissanite's physical properties and how to verify authenticity at home, see our article on how to spot fake moissanite. Explore our full collection of GRA-certified moissanite rings and earrings.